Avalanche Forecast

Archived

Feb 28th, 2022–Mar 1st, 2022

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Cariboos.

Triggering avalanches is likely on freshly wind loaded slopes. Seek out sheltered terrain.

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

MONDAY NIGHT: Cloudy with isolated flurries and up to 5 cm of new snow, moderate wind from the southwest, treeline temperatures around -5 C.

TUESDAY: Cloudy with scattered flurries bringing 5-10 cm of snow, moderate wind from the southwest, treeline temperatures around -5 C with freezing level climbing to 1500 m in the western Cariboos and 1000 m in the eastern Cariboos.

WEDNESDAY: Mostly cloudy skies with isolated flurries bringing up to 5 cm of snow, light wind from the south, treeline temperatures around -6 C.

THURSDAY: Mix of sun and cloud, light wind from the northwest, treeline temperatures around -6 C.

Avalanche Summary

Over the weekend there were some isolated reports of human triggered wind slab avalanches. They were mostly small (size 1) avalanches in the top 20 cm of new snow, although one size 2 slab was triggered by a rider on a northeast aspect near Valemount and another size 2 slab was triggered by a cornice fall. The addition of more snow since then has increased the potential size of wind slab avalanches. The last report of a persistent slab avalanche was on Feb 12 near Blue River.

Snowpack Summary

Flurries throughout the day on Tuesday will bring recent storm totals to 10 to 25 cm of fresh snow, with the greatest accumulations around Blue River. This snow covers a wide variety of hard surfaces, including heavily wind-affected snow on alpine slopes and a sun crust on steep south-facing slopes, as well as some large feathery surface hoar crystal in sheltered areas. Two layers of melt-freeze crusts and/or surface hoar can be found 50 to 100 cm deep, but we have seen declining amounts of evidence that these layers still remain a problem in the Cariboos. We recommend extra caution around freshly loaded slopes in the Blue River / Clearwater area where these layers may still be possible to trigger.

Terrain and Travel

Be carefull around freshly wind loaded features.
Caution around convexities or sharp changes in terrain.
Use ridges or ribs to avoid areas of wind loaded snow.
Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.